2016 Silverado lt4 swap high pressure in fuel rail

[turbocorey]

i have a 2016 1500 silverado with a v6 work turck . i got a lt4 from the dealer. the ecm is from a 2017 1500 as the lt4 is a 2017 .

i do have a 3 wire fps
the new wire that is from a 2016 is a 4 wire fps( i moved the blue wire from the black plug and put it in the blue pulg this makes the 4 wire to a 3 wire)
the ecm is a 3 wire

the problem i am having is my fuel rail pressure is 95,050 and keeps fowling out my plugs

[turbocorey]

need help

[radrace19]

Just leave the stock ECU in the truck and put the correct fuel rail pressure sensor on the LT4 engine. That should fix the problem I think.

[turbocorey]

the stock ecu was for a v6. the fuel rail sensor is the same as the ecu . the wiring was for the 4 wire but now it is a 3 wire

[206whips]

Having the same issue on a swap 2018 engine with 2018 ecu fuel rail psi 95050.5 psi need to figure this out.

[turbocorey]

i still have not figure this out . when i do i will post what it was hope you do the same

[206whips]

I disconnected bank 1 and bank 2 injector harness from behind the supercharger and the fuel rail pressure is still reading the same 95050.5 psi kinda all the way confused now unless not being connected makes it read high plugged bank plug into bank 1 on the harness no difference gonna go try bank 1 plug in to bank 2 on the harness and see if it makes a difference

[turbocorey]

i have done that and didnt work . it will still read the same.

[206whips]

Your right tried it no difference

[206whips]

where did you get your swap harness from?

[turbocorey]

i used the factory harness brand new from gm (6.2 harness)

[radrace19]

the stock ecu was for a v6. the fuel rail sensor is the same as the ecu . the wiring was for the 4 wire but now it is a 3 wire

This is the problem. The ECM is programmed for a 4 wire pressure sensor. So you need the 4 wire rail sensor and the correct injector harness for that bank of injectors and sensor.
You can not mix and match to my knowledge.

[turbocorey]

the ecu is a 3 wire ecu not a 4 wire

[turbocorey]

the fix for me is that the harnesses needed to be a 3 wire .so i repinned the harnesses to a 3 wire and it fixed it